Still More on the 1/f2 Phase Noise Performance of Harmonic Oscillators
Author
Summary, in English
Modeling tank losses in a harmonic oscillator by means of an equivalent parallel resistance may lead to an optimistic estimate of phase noise, as recently experienced in a class-D CMOS oscillator. The discrepancy is significant if two conditions are fulfilled: The single-ended portion of the tank capacitance displays a non-negligible loss, and the loop gain of the oscillator is very large; in the latter case, a phase noise boost is likely to occur. In this brief, we derive phase noise equations that capture such behavior in a class-B oscillator, which is easier to approach than a class-D oscillator. The results, however, are (qualitatively) valid in general. Furthermore, the phase noise caused by the oscillator active core is always proportional to the phase noise caused by the tank losses independently of the amount of phase noise boost. The agreement between theoretical and simulation results is excellent.
Department/s
Publishing year
2016-06-01
Language
English
Pages
538-542
Publication/Series
IEEE Transactions on Circuits and Systems II: Express Briefs
Volume
63
Issue
6
Document type
Journal article
Publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
Topic
- Signal Processing
Keywords
- Impulse sensitivity function (ISF)
- oscillators
- phase noise
Status
Published
ISBN/ISSN/Other
- ISSN: 1549-7747